Serine protease inhibitor activity of recombinant squamous cell carcinoma antigen towards chymotrypsin, as demonstrated by sodium dodecyl sulfatepolyacrylamide gel electrophoresis

Abstract
Squamous cell carcinoma (SCC) antigen was tested, by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, for its ability to inhibit the activity of serine proteases, i.e., trypsin, chymotrypsin and elastase. We demonstrated that the serine protease inhibitor (serpin) of SCC antigen is specific for chymotrypsin. Preincubation of chymotrypsin with recombinant SCC antigen inhibited chymotryptic digestion of gelatin and ovalbumin through the formation of sodium dodecyl sulfate-stable complexes. These findings promote understanding of the biological functions of SCC antigen as serpin in the stratification of the normal squamous cells and in the malignant behaviour of the tumor cells.